Some things that happened to us and what to look for:
Sibling puppies will quickly bond to each other leaving you the odd man out
Training is extremely difficult as they focus on each other and not you
It is safer to train them individually and by themselves
You must separate them at times to allow for bonding with you and not eachother
If separated, they can have intense levels of anxiety in which we deal with our Maggie when she cannot see Jake
Having two puppies the same age at the same time can hinder their socialization skills and they can become fearful or reactive to other dogs
One of the reasons you see distress in the first photo is that Jake And Maggie thought they were going to be separated. I learned while raising them and spending almost every waking minute with them that this is the look of fear.
The pups will not go outside without the other. They both have to be outside at the same time.
It is extremely difficult to train a dog during loose leash training while you have another the same age as they do not pay attention
The energy of one puppy can be fun but tiring. Can you imagine two puppies at the same time!
I cannot stress enough that if you do not have the time and your schedule does not permit training to littermates at the same time, DO NOT get them. We wanted Jake And Maggie to be together as they did not come from the greatest environment. I was home full-time with them but it took much patience. To say it was easy, I would be lying.
If you take the time to learn what it takes to train siblings or two puppies at the same time, hire a trainer, ask questions, show patience, do your research. Trust me. You will need to learn all you can. Animals are incredible. A well-trained animal makes all the difference. You will be so glad you made the investment in them because they will return all the love ten fold.